1. Field of the invention
The present invention relates to cooling of electronic devices, and particularly to a heat sink assembly having a fixing device for readily and firmly attaching a fan to a heat sink.
2. Related art
Developments in today""s highly information-intensive society have led to remarkable improvements in performances of electronic devices. During operation of many contemporary electronic devices, large amounts of heat are produced. Such heat must be efficiently removed from the electronic device, to prevent the system from becoming unstable or being damaged. Typically, a heat sink is attached to an outer surface of the device to facilitate removal of heat therefrom. A fan is often attached to the heat sink to provide forced air convection therefrom.
FIG. 3 shows a conventional heat sink assembly, which includes a heat sink 3, a fan 4 and a plurality of screws 5. The heat sink 3 has a base 31, and a plurality of heat dissipating fins 33 extending upwardly from the base 31. The fan 4 is essentially a rectangular box, with a through hole 41 defined in the vicinity of each corner thereof. In assembly, a tool such as a screwdriver (not shown) must be used to drive the screws 5 through the corresponding through holes 41 such that the screws 5 engage with the fins 33 of the heat sink 3. Disassembly also requires such tool, making these procedures unduly cumbersome and complicated. Furthermore, there is an industry trend whereby the fins 33 are being made thinner and thinner. Thus the fins 33 are more frequently being distorted or even damaged when the screws 5 are engaged therewith.
Therefore, an improved means of securing a fan to a heat sink which overcomes the above problems is desired.
Accordingly, an object of the present invention is to provide a heat sink assembly having a fixing device which firmly and safely attaches a fan to a heat sink.
To achieve the above-mentioned object, a heat sink assembly comprises a heat sink, a frame, a fan, and a fastener. The heat sink has a pair of poles extending upwardly from diagonally opposite corners of a base thereof. An annular step is formed at an upper portion of each pole, at a position higher than a top extremity of fins of the heat sink. An annular groove is defined in the vicinity of a top end of each pole. The frame has a central opening, and a pair of apertures at diagonally opposite corners of the frame. A through hole is defined in each of four corners of the fan. The fastener has two mutually perpendicular fixing arms. Each fixing arm defines a semicircular cutout at an inner edge of a free end thereof. The fixing arms at the cutouts engage in the grooves of the poles, thereby securing the fan to the heat sink.
Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of a preferred embodiment of the present invention together with the attached drawings, in which: